1. Field of the Invention
The invention relates to mixtures of polymerized mono- and dicarboxylic acids and more particularly relates to tricarboxylic acids obtained from the reaction of unsaturated dicarboxylic acids containing 16, 17, 18, 20, or 22 carbon atoms or mixtures thereof with monocarboxylic acids containing 18 carbon atoms.
2. Brief Description of the Prior Art
It is well known that unsaturated fatty acids, particularly those derived from natural sources, are capable of being converted to dimer and trimer forms. This is usually realized by heating the unsaturated fatty acids in the presence of catalytic proportions of a mineral clay and, preferably, an acid-treated mineral clay, at temperatures in excess of about 180.degree. C. with water under autogenous pressure. Representative of the prior art teachings are those found in the U.S. Pat. Nos. 2,793,219 and 2,793,220.
We have now discovered that unsaturated dicarboxylic acids having 16, 17, 18, 20, or 22 carbon acids, alone or in admixture, and monocarboxylic acids having 18 carbon atoms, will react with each other under the influence of clay catalysts to yield tricarboxylic acids of 34, 35, 36, 38 or 40 carbon atoms having unique and useful properties.